For my TinyMobot project ( Tiny24hourMoBot #5 : Post Script - Making it even Tinier ) I have been looking for some smaller motors to replace the continuous rotation micro servo motors I currently use. I have ordered a selection of various types, including some small stepper motors and the first of these have arrived.
There are micro DC motors approximately 8 mm long and 4 mm in diameter. They are designed to be vibrators in mobile phones so come with an off-centre weight attached. I didn't really appreciate how small this is and I think they might be just too small for me to be able to use effectively, see video below
As indicated in the video to be useful the off-centre weight has to be removed which can be done using two sets of pliers, one to hold the motor body (after removing the black rubber shroud, by the rim near the shaft, and a second set of pliers to hold the off-centre weight. A short, sharp 'tug' between the two pliers will usually remove the off-centre weight. Unfortunately, if too much force is used or the grips are not quite correct, the connecting wires can be removed or the whole commutator comes off, see photograph below.
I used the best close-up shot I could get with my camera which has a closeup macro feature especially for taking photographs of PCBs and soldered joints and I still had a great deal of trouble getting a shot even remotely in focus. The parts are so small that the camera tends to focus on the background, so I have a nice in-focus shot of the 'smooth' surface of my desk. But if you look carefully you can just see the two commutator springs in the black round bit on the left, and the shaft of the armature inside the cylindrical casing on the right.
I hope that some of the other motors are a bit bigger and more suitable for my purpose.